| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2015 | 9.22 | 23 |
| 2014 | 3.15 | 90 |
| 2013 | 6.71 | 36 |
| 2012 | 8.28 | 37 |
| 2011 | 6 | 55 |
| 2010 | 6.8 | 48 |
| 2009 | 5.6 | 54 |
| 2008 | 8.83 | 43 |
| 2007 | 7.66 | 67 |
| 2006 | 7.64 | 54 |
| 2005 | 5.41 | 63 |
| 2004 | 3.38 | 87 |
| 2003 | 1.32 | 126 |
| 2002 | 4.39 | 54 |
| 2001 | 10.7 | 14 |
| 2000 | 5.02 | 53 |
| 1999 | 0.04 | 163 |
| 1998 | 2.51 | 90 |
| 1997 | 2.22 | 87 |
| 1996 | 3.26 | 39 |
| 1995 | 3.88 | 37 |
| 1994 | 2.69 | 35 |
| 1993 | 1.72 | 53 |
| 1992 | 3.43 | 24 |
| 1991 | 4 | 19 |
| 1990 | 1.05 | 62 |
| 1989 | -.02 | 121 |
| 1988 | -.06 | 127 |
| 1987 | -.01 | 121 |
| 1986 | 0.5 | 67 |